Résumé
In forensic medicine, the demand for bone age estimation has been growing noticeably in recent years with the increasing global flow of people. According to the latest international recommendations outlined by the Study Group on Forensic Age Diagnostics (AGFAD) in 2016, bone age estimation is based on a clinical examination, hand radiograph, orthopantomogram and clavicle CT scan. The orthopantomogram uses the mineralization stage of the mandibular 3rd molar according to the Demirjian method. The aim of this study is to validate the Demirjian method in CT to be able to perform only a CT-scan of the mandible and the clavicles. This is an exhaustive study of 201 cases from the University Hospital of Montpellier concerning all living persons, aged 0 to 25 years, who had anorthopantomogram and a CT-scan less than two months apart, between 2007 and 2020. We compare the stages attributed to the mandibular 3rd molars in the two techniques and perform a second reading of 50 cases by the same radiologist and by a forensic physician. The concordance calculation between the two techniques shows an almost perfect agreement with a weighted kappa of 0.86 for the 128 left mandibular 3rd molars analyzed and 0.88 for the 126 right mandibular 3rd molars analyzed. Calculations of intra- and inter-observer agreement in CT also show almost perfect agreement for intra-observer variability with kappa of 0.97 and 1.0, and strong agreement for inter-observer variability with kappa of 0.86 and 0.73. The main limitation of this study is the small number of patients, which does not allow a sufficiently robust study of the correlations with the real age of the patients, but it does allow the validation of the Demirjian method in CT-scan.